Scientists
use different kinds of investigations depending on the questions
they are trying to answer. Types of investigations include describing
objects, events, and organisms; classifying them; and doing a fair
test (experimenting). (K-4)

Different
kinds of questions suggest different kinds of scientific investigations.
Some involve observing and describing objects, organisms, or events;
some involve collecting specimens; some involve experiments; some
involve seeking more information; some involve discovery of new
objects and phenomena; and some involve making models. (5-8)

Objects
have observable properties, including size, weight, shape, color,
temperature, and the ability to react with other substances.
Those properties can be measured using tools, such as rulers,
balances, and thermometers. (K-4)

The
sun is a major source of energy for changes on the earth's surface.
The sun loses energy by emitting light. A tiny fraction of that
light reaches the earth, transferring energy from the sun to the
earth. The sun's energy arrives as light with a range of wavelengths,
consisting of visible light, infrared, and ultraviolet radiation.
(5-8)

Organisms
have basic needs. For example, animals need air, water and food;
plants require air, water, nutrients, and light. Organisms can
survive only in environments in which their needs can be met. The
world has many different environments, and distinct ones support
the life of different types of organisms. (K-4)

An
organism's behavior patterns are related to the nature of that
organism's environment, including the kinds and number of other
organisms present, the availability of food and resources, and
the physical characteristics of the environment. When environment
changes, some plants and animals survive and reproduce, and others
die or move to new locations. (K-4)

Reproduction
is a characteristic of all living systems; because no individual
organism lives forever, reproduction is essential to the continuation
of every species. Some organisms reproduce asexually. Other organisms
reproduce sexually. (5-8)

Millions
of species of animals, plants, and microorganisms are alive today.
Although different species might look dissimilar, the unity among
organisms becomes apparent from an analysis of internal structures,
the similarity of their chemical processes, and the evidence of
common ancestry. (5-8)

Biological
evolution accounts for the diversity of species through gradual
processes over many generations. Species acquire many of their
unique characteristics through biological adaptation, which involves
the selection of naturally occurring variations in populations.
Biological adaptations include changes in structures, behaviors,
or physiology that enhance survival and reproductive success in
a particular environment. (5-8)

Objects
in the sky have patterns of movement. The sun, for example, appears
to move across the sky in the same way every day, but its path
changes slowly over the seasons. The moon moves across the sky
on a daily basis much like the sun. The observable shape of the
moon changes from day to day in a cycle that lasts about a month.
(K-4)

The
sun is the major source of energy for phenomena on the earth's
surface, such as growth of plants, winds, ocean currents, and the
water cycle. Seasons result from variations in the amount of sun's
energy hitting the surface, due to the tilt of the earth's rotation
on its axis and the length of the day. (5-8)

Tools
help scientists make better observations, measurements, and equipment
for investigations. They help scientists see, measure, and do
things that they could not otherwise see, measure, and do.(K-4)

Many
individuals have contributed to the traditions of science. Studying
some of them provides further understanding of scientific inquiry,
science as a human endeavor, the nature of science, and the relationships
between science and society. (5-8)